One Dimensional pi-Conjugated Band Dispersion In Polymeric Chains
DIPC Seminars
- Speaker
-
Guillaume Vasseur, Institut Jean Lamour, Université de Lorraine-CNRS, France
- When
-
2014/05/19
14:00 - Place
- Donostia International Physics Center (DIPC).Paseo Manuel de Lardizabal, 4, Donostia
- Add to calendar
- iCal
**_One Dimensional Pi-Conjugated Band Dispersion In Polymeric Chains_**
** **
G.Vasseur1, Y. Fagot-revurat1, J. Lipton-Duffin2, V. Meunier3, M. Di
Giovannantonio4, D. Perepichka5, L. Cardenas2, G. Contini4, F.Rosei2,
D.Malterre1
_ _
_1_ _. Institut Jean Lamour, Université de Lorraine - CNRS, Vandoeuvre-les-
Nancy, France_
_2_ _. Institut National de la Recherche Scientifique, Varennes, Canada_
_3_ _. Department of Physics, Applied Physics, and Astronomy, Rensselaer
Polytechnic Institute, New York, United States_
_4_ _. Istituto di Struttura della Materia, CNR, Roma, Italy_
_5_ _. Department of Chemistry and Centre for Self-Assembled Chemical
Structures,McGill University, Montreal, Canada._
_ _
During the last two decades, the development of novel architectures based on
molecular or supramolecular devices becomes a key challenge in the field of
nanotechnology. The functionalization of surfaces by self-assembling of
covalently bounded networks from single molecular building blocks is an
increasing popular field with potential applications in nano-electronic and
optoelectronic [1]. In this way, the synthesis and assembly of Pi-electron
functional organic molecules has been recently studied extensively [2].
_ _
In the context of a collaboration between the INRS (Montréal), the ISM (Rome)
and the IJL (Nancy), a surface-catalyzed dehalogenative polymerization has
been evidenced for the (1,4)-dibromobenzene (DBB) on copper (110) interface by
combining scanning tunneling microscopy (STM), X-ray photoelectron
spectroscopy (XPS), low energy electron diffraction (LEED), near edge X-ray
absorption fine structure spectroscopy (NEXAFS) and first-principles
calculations [3]. Above 200°C, the organometallic (OM) intermediate, obtained
for room temperature deposition, polymerize into a very well organized 1D
polymer formed by phenyl cycles assembled in arm-chair configuration.
Similarly, the same dynamic can be evidenced for diiodobenzene (DIB)
evaporated on copper (110). During this seminar I will present our last
results on electronic properties of organometallic and polymeric phases for
DBB and DIB investigated by STS and ARPES. First, we will discuss on the
chemical sensitivity in STS to metallic bonds which allowed us to determine
the structure of two new organometallic phases for DIB and 1ML-DBB / Cu(110).
Then I will focus on the study of a "transverse" polymer formed at the
saturation of the surface. ARPES intensity maps allowed us to identify a one
dimensional graphene-like strongly dispersive Pi-band on 7.2 eV, below the
Fermi energy, interpreted as a consequence of the polymerization process. By
STS we also observed LUMO's confined states for small chains over the Fermi
level. By increasing the length of chains, the loss of confinement induces
the formation of a continuous dispersive band which crosses the Fermi energy,
conferring a metallic character to the polymer.
[1] L. Grill, M. Dyer, L. Lafferentz, M. Persson, M.V. Peters and S. Hecht,
Nature nanotech. **2** , 687-691 (2012)
[2] J. Cai, P. Ruffieux, R. Jaafar, M. Bieri, T. Braun, S. Blankenburg, M.
Muoth, A.P. Seitsonen, M. Saleh, X. Feng, K. Mullen and R. Fasel, Nature
**466** , 470-473 (2010)
[3] M. Di Giovannantonio, M. El Garah, J. Lipton-Duffin, V. Meunier, L.
Cardenas, Y. Fagot Revurat, A. Cossaro, A. Verdini, D.F. Perepichka, F. Rosei
and G. Contini, ACS Nano **7** , 8190 (2013)